People often cover the cover to the main body of the toilet conveniently to reduce the smell of the toilet, as a result, the frequency of opening and closing the cover is high, and the key is the joining component between the cover and the main body of the toilet, of which the stability and reliability are highly concerned. The joint of the cover and the main body of the toilet is directly achieved by some simple rotating joint at the prior art, and there is no resistance to prevent the cover hitting the main body of the toilet heavily when people lay the cover down, so that the rotating joint between the cover and the main body of the toilet and the cover or the main body of the toilet are easy to be damaged. To solve the problem above, many shaft mechanisms are present to achieve damping, of which one important characteristic is to get the effect of one-way valve by using blades: the blades block the passage of the damping oil to form the slow flowing effect of the cover when the pivot rotates ahead one direction, the blades open the passage of the damping oil to form the fast flowing effect of the cover when de pivot rotates ahead another direction. But there are several structural defects of the above mechanisms such as complication of the working technique, limitation of the structure and the intensity, shortage of the service life, and more special, the damping of the cover during the whole falling process is not convenient to use.